Turbo Prolog

F Glossary
anonymous variable The variable "_" used in place of an ordinary variable when the
values that the ordinary variable may become bound to are of no interest.
arguments Collective name for the objects and variable names in a relation.
atom A relation, possibly involving objects or variables.
attribute A positive whole number that determines the characteristics of the display
in a given window, including color, blinking/non-blinking and normal/inverse video.
backtracking The mechanism built into Turbo Prolog whereby, when evaluation of a
given sub-goal is complete, Turbo Prolog returns to the previous sub-goal and tries to
satisfy it in a different way.
bound variable A variable that refers to a known value.
calling a sub-goal (or predicate) An expression denoting that Turbo Prolog is now
trying to satisfy a certain sub-goal (belonging to the given predicate).
char An arbitrary character enclosed between two single quotation marks.
compiler directives Instructions to the Turbo Prolog compiler to take special actions.
clause A fact or rule for a particular predicate, followed by a period (.).
compound goal A goal containing at least two sub-goals.
compound object An object consisting of a functor and a list of objects separated by
commas and enclosed in parentheses.
current input device The currently assigned readdevice from which standard predicates
take input by default.
current output device The currently assigned writedevice to which standard predicates
send output by default.
cut (or!) The cut commits Turbo Prolog to all the choices made so far in the evaluation
of the predicate containing the cut. Once the cut has been evaluated as a sub-goal,
Turbo Prolog may not backtrack past it.
database predicates Predicates for which facts can be added to or deleted from the
Turbo Prolog system during execution.
dialog window The system window in which external goals are given and the results
of those goals recorded.
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